Various systems for enhancing the vision of pilots in low visibility environments are available. Such environments include operations at nighttime, during periods of low cloud cover, in stormy weather, through smoke clouds, or combinations of the above and the like.
One current system in use on the C-130 and C-141 military aircraft is a turret-mounted Forward-Looking Infrared (FLIR) sensor typically mounted to the underside of the front of the aircraft. This system requires a dedicated operator/crew member (navigator) who controls the turret's movement and relays the information to the pilot. The image is presented on a Head-Down-Display (HDD). Unfortunately, such a FLIR turret can be disorienting because the sensor is not always pointed in the same direction as the viewer's gaze. Furthermore, the turret and associated ball-mechanism extend outward from the skin of the aircraft, and thus presents a source of aerodynamic drag. Moreover, the various moving parts of the turret reduce the reliability and Mean Time Between Failures (MTBF) of the system.
Another approach to enhance a pilot's vision is the use of night vision goggles. In contrast to infrared sensors, which respond to thermal differentials, night vision goggles can only see objects that radiate at least a minimum of light energy to the goggles, and thus cannot “see” through dense cloud cover, for example. For this same reason, night vision goggles require a window to see through. Night vision goggles have a relatively limited field of view, so-called “tunnel vision,” that requires aggressive scanning for situational awareness and spatial orientation, thus increasing the workload and physical fatigue of the pilot or navigator. Additionally, large or intense light sources may tend to cause night vision goggles to “bloom” such that the image is blurred.
Another vision enhancement system utilizing an array of staring sensors fixed to a host platform (e.g., an aircraft) is disclosed in U.S. Pat. No. 5,317,394 to Hale, et al. The term “staring” refers to a sensor that has a fixed viewpoint, as opposed to a turret-mounted sensor, for example. Each sensor produces signals corresponding to positions of objects within a field of view over time. At least one sensor signal memory receives those signals and stores them in a manner enabling concurrent access to signals received from any selected combination of sensors. The processing unit and associated memory contain at least one program for selecting sensor signals from a sensor signal memory, and producing a selected image on a display, such as a CRT or LED attached to an operator's headgear.
Despite these attempts to improve visibility, there is still a need for a more robust system that provides enhanced visibility without unduly interfering with the pilot's many operational tasks onboard the aircraft.